JP2503480Y2 - Concrete detector - Google Patents

Description

[Detailed Description of the Invention] << Industrial Application Field >> This invention is, for example, for the top end of the cast concrete (the boundary between the underwater concrete and the muddy water above it) when the concrete is poured into water by the tremie method. It relates to a concrete detector used, for example, for measuring position.

<Prior art> In the tremie method, it is necessary to grasp the top level of the underwater concrete during pouring as accurately as possible in order to properly control the pulling position of the tremie pipe. Therefore, various concrete detectors and measuring methods have been developed.

JP-B-54-7705 discloses that the temperature of concrete before solidification placed in water and the temperature of the muddy water above it are detected by temperature sensors, respectively, and the temperature of the concrete and muddy water is increased and lowered. A technique for measuring where the boundary is located is disclosed.

In addition, Japanese Utility Model Laid-Open No. 62-3849 uses a float whose buoyancy is adjusted to sink in muddy water and float in concrete, and a mechanism that detects whether the float is floating or sinking with an inclination sensor (mercury switch). A device attached with is disclosed.

《Problems to be solved by the invention》 In the conventional technology of measuring the top level of concrete using the difference in temperature between concrete and mud, there are many construction states in which the temperature difference between concrete and mud is not clear,
There was a problem that the concrete top level could not be reliably detected.

In the conventional technology that detects the top of the concrete with a float and an inclination sensor, the floating float mechanism is easily damaged by impact in concrete containing aggregate such as gravel, especially when a reinforced basket is used. Since the system and the reinforced cage damped, the probability of breakage was high, and it could hardly be used.

The present invention has been made in view of the above-mentioned conventional problems. It has a simple structure, can be implemented at low cost, and has a robust structure that does not impair the function even if it is repeatedly used in concrete. To provide a container.

<< Means for Solving the Problems >> A concrete detector according to the present invention is a casing pipe that is inserted into concrete before being solidified and is filled with muddy water, and a predetermined portion of the casing pipe. A window hole formed in the casing pipe, a diaphragm fixedly attached to the casing pipe so as to cover the window hole, and integrally including a detection target, and the inside of the casing pipe facing the inner surface side of the diaphragm. A sensor that is fixed and that detects the approach and separation of the detected object without contact is provided.

<< Operation >> In the measurement state, the pressure of the muddy water acts on the inside of the casing pipe, and the pressure of the cast concrete before solidification acts on the outside of the pipe. Therefore, a differential pressure between muddy water pressure and concrete pressure acts on the diaphragm, so that the diaphragm is pushed inside the pipe and bends. Since the diaphragm integrally includes the detected object, when the diaphragm bends inward, the detected object approaches the sensor.

If the part of the diaphragm is in muddy water rather than in concrete, the above-mentioned differential pressure does not act on the diaphragm and the diaphragm does not bend. Therefore, by discriminating the sensor output, it is possible to determine whether the diaphragm portion is in concrete or in muddy water.

<Example> Fig. 3 shows a situation in which the concrete detector according to the present invention is applied to the tremy method of a continuous underground wall.

The tremie pipe 2 is installed almost vertically in the muddy water 1 of the ditch where a continuous underground wall is to be constructed and held at an appropriate height, concrete is poured from the upper end of the tremie pipe 2 and from the lower end of the tremie pipe 2. Concrete is poured into muddy water 1. 3 is the poured underwater concrete.

The casing pipe 4 of the concrete detector of the present invention is attached to a side portion of the tremie pipe 2 through a bracket 5 in parallel with the pipe 2, and is placed almost vertically in the muddy water 1 and the concrete 3 together with the tremie pipe 2. .

The lower end of the casing pipe 4 is closed and the upper end is opened. A fine mesh 6 is attached to the upper opening of the pipe 4 so that the pipe 4 is filled with the muddy water 1 while preventing concrete from entering the pipe 4.

Eight proximity switches 7 are mounted in the casing pipe 4 with a structure described in detail below at predetermined intervals in the longitudinal direction. FIG. 1 and FIG. 2 show details of the structure of the mounting portion of the proximity switch 7.

As shown in FIGS. 1 and 2, circular window holes 4a are formed in the outer peripheral portion of the casing pipe 4 at predetermined intervals, and are made of rubber so as to close the window holes 4a from the outside. The diaphragm 8 is in close contact with the pipe 4, and the diaphragm 8 is fixed to the pipe 4 via a ring-shaped holding plate 9 and bolts 10.

In the central portion of the diaphragm 8, the above-mentioned magnetic rubber plate 8a as a detected body is built. The magnetic rubber plate 8a is integrated by insert molding so as to be embedded in the diaphragm 8, or the magnetic rubber plate 8a is laminated in the diaphragm 8 having a laminated structure.

The proximity switch 7 is the window hole 4a of the casing pipe 4
It is fixed to the inside of the via a mount 11. Head cover made of epoxy resin on the head of the proximity switch 7.
12 is covered, and this head portion is located at the center of the window hole 4a and is embedded in the diaphragm 8 a magnetic rubber plate 8a.
And are arranged with a predetermined interval. A plurality of water guide holes 11a are formed in the mount 11 so that the muddy water 1 in the pipe 4 enters the space between the head portion of the proximity switch 7 and the diaphragm 8.

The signal cable 13 of each proximity switch 7 is routed through the pipe 4 to a display device 14 installed on the ground as shown in FIG.

In the configuration described above, in the state shown in FIG. 3, the upper two of the eight proximity switches 7 are located in the muddy water 1, and the remaining lower six are located in the cast underwater concrete 3.

Assuming that the proximity switch 7 shown in FIG. 1 is located in this concrete 3, the pressure of the concrete 3 acts on the outer surface side of the diaphragm 8 in this part, and the inside of the diaphragm 8 is filled in the pipe 4. The pressure of the flowing muddy water 1 acts. The diaphragm 8 bends due to the pressure difference between the inside and the outside, but naturally the pressure of the concrete 3 is much larger, so the diaphragm 8 bends inward.
Then, the magnetic rubber plate 8a embedded in the diaphragm 8 approaches the head portion of the proximity switch 7,
The output of this proximity switch 7 is turned on.

Further, assuming that the proximity switch shown in FIG. 1 is located at the position of the muddy water 1, the same pressure of the muddy water 1 acts on the outer surface side and the inner surface side of the diaphragm 8, so that there is no pressure difference between the inside and the outside of the diaphragm 8. 8 does not bend. Therefore, the distance between the magnetic rubber plate 8a and the proximity switch 7 is large, and the output of the proximity switch 7 is OFF at this time.

In the display device 14 of FIG. 3, the top level of the concrete 3 is detected by the output signal of each proximity switch 7 and displayed in the form of a bar graph, for example. In the example of FIG. 3, the outputs of the upper two proximity switches are OFF, and the outputs of the third and subsequent proximity switches 7 are all ON, so the top level of the concrete 3 is the second from the top. It can be seen that it is between the third proximity switch and the third proximity switch.

In the above embodiments, the proximity switch was used as a sensor that is provided integrally with the diaphragm and that detects the approach and separation of the detected object in a non-contact manner, but the present invention is not limited to this, and the detected object is If the sensor system is configured so as to obtain an output of a level corresponding to the distance between the sensor and the sensor, the degree of deflection of the diaphragm, that is, the pressure difference between the inside and outside of the diaphragm can be detected. That is, it can also be used as a differential pressure gauge for detecting the difference in pressure acting on the inside and outside of the diaphragm.

<Effect of device> As described in detail above, the concrete detector according to the present invention has a simple structure in which a diaphragm made of rubber or the like is attached to part of it when viewed from the outside of the casing type. Since it is a structure, it has a robust structure with little damage even in concrete containing aggregate such as gravel, and it is a durable concrete detector that can be used for a long period of time. In addition, the principle of concrete detection is sensitive to the difference between the pressure of placed concrete and the pressure of muddy water, so unlike concrete detection based on conventional temperature, there is a clear difference in concrete pressure and muddy water pressure in any construction condition. Based on and, concrete can be detected accurately. That is, the top level of concrete can be detected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the main part of a concrete detector according to an embodiment of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a schematic configuration diagram of the concrete detector according to the present invention attached to a tremie pipe. is there. 1 …… Muddy water, 2 …… Tremy pipe 3 …… Underwater concrete 4 …… Casing pipe 4a …… Window hole, 5 …… Bracket 6 …… Mesh, 7 …… Proximity switch 8 …… Diaphragm, 8a …… Magnetic rubber Plate 9 …… Presser plate, 10 …… Bolt 11 …… Mount, 11a …… Water guide hole 12 …… Head cover, 13 …… Signal cable 14 …… Display device

Claims (1)

(57) [Scope of utility model registration request] 1. A casing pipe that is inserted into concrete before being solidified and is filled with muddy water, a window hole formed in a predetermined portion of the casing pipe, and the window hole is closed. As described above, the diaphragm is fixed to the casing pipe and integrally includes the detection target, and the diaphragm is fixed inside the casing pipe so as to face the inner surface side of the diaphragm.
A concrete detector equipped with a sensor for detecting detachment without contact.